In typical cellular mobile communication, a mobile station (MS) sends an uplink data packet to a base station (BTS) transceiver over the air and the base station forwards the received packet toward a radio network controller (RNC) which then sends it to an appropriate upper layer, e.g. Internet. To support efficient uplink packet transmission from multiple mobile stations in the mobile communication network, the base station schedules the multiple mobile stations in order to maximize the total uplink data throughput of a cell while meeting a service requirement of individual mobile stations.
As an example uplink data packet scheduling, FIG. 1 illustrates the Enhancement of Uplink Dedicated Channel (EDCH) in WCDMA (Wideband Code Division Multiple Access) mobile system. In the EDCH scheme, mobile stations (MS1, MS2) 101, 102 are transmitting multiple data flows (e.g. multiple data services) in uplink. The data transmission of uplink is controlled by base station scheduler 103. Uplink capacity request messages 104 and downlink capacity assignment messages 105 are exchanged between the mobile stations and the base station. Dynamic uplink radio resource allocation (in other words, uplink interference reshuffling) is implemented by closed loop capacity control among multiple mobile stations as shown in box 106 which illustrates uplink scheduling of mobile stations performed by a base station. Such scheduling is disclosed in, for example, each standard of: 3GPP TS 25.309 V6.0.0; 3GPP TR 25.808 V0.2.3; and 3GPP TR 25.909 V0.1.0.
In a most mobile communication system, there are two sub-systems to support a delivery of user data to designation, namely a radio layer and a transport layer. The radio layer performs a transmission of user data over the air between a mobile station and a base station while the transport layer carries out the delivery of the user data between the base station and other element of network, e.g., a radio network controller. Therefore, the overall network capacity is limited by both radio layer capacity and network layer capacity.
When a certain mobile station requests to establish uplink packet transmission, the radio network controller checks whether both radio layer and transport layer have sufficient available capacity to accommodate the mobile station. Furthermore, after the mobile station is admitted, a new radio link can be added when quality of the new radio link is sufficiently high compared to already added radio links. Note that the radio link refers to a wireless radio connection between a mobile station and a base station. Increased number of radio links improves the radio link capacity due to diversity handover gain.
In mobile communication, the radio layer capacity can be also improved by Automatic Request for Repeat (ARQ) which allows fast recovery of data transmitted over fast fading radio channel condition. This ARQ technique is more useful technology to transmit delay insensitive data such as interactive and background service than delay critical data such as voice service. A simple type of ARQ technology is used in an uplink transmission system such as Enhanced DCH (refer 3GPP TR 25.808 V0.2.3). Note that the mobile communication system such as Enhanced DCH technology uses the ARQ technique in conjunction with diversity handover technique, hence enabling even higher capacity gain of radio link capacity.
The standards of 3GPP (3rd Generation Partnership Project) cited in this description will be listed below:
[Non-patent Document 1] 3GPP TS 25.309 V6.0.0 (2004-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; FDD Enhanced Uplink; Overall description; Stage 2 (Release 6);
[Non-patent Document 2] 3GPP TR 25.808 V0.2.3 (2004-10) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; FDD Enhanced Uplink; Physical Layer Aspects (Release 6); and
[Non-patent Document 3] 3GPP TR 25.909 V0.1.0 (2004-09) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; FDD Enhanced Uplink: UTRAN lub/lur Protocol Aspects (Release 6).